Colored double-knit fabric material of cellulose organic acid ester having less than 0.29 free hydroxyl groups per anhydroglucose unit



States Patent 3,449,058 COLORED DOUBLE-KNIT FABRIC MATERIAL OF CELLULOSEORGANIC ACID ESTER HAVING LESS THAN 0.29 FREE HY DROXYL GROUPS PERANHYDROGLUCOSE UNIT David H. Hellman, Livingston, N.J., and Joseph S.

Warner, Charlotte, N.C., assignors to Celanese Corporation, New York,N.Y., a corporation of Delaware No Drawing. Filed Jan. 7, 1965, Ser. No.424,130 Int. Cl. D06p 3/82, 3/40 US. Cl. 824 13 Claims ABSTRACT OF THEDISCLOSURE A colored double-knit fabric material free of distortion inthe courses and wales of the double-pique stitch and having substantialretention of stitch definition, the fibers of which are substantiallyfree of brittleness and comprise a cellulose organic ester of lowhydroxyl content produced by contacting the uncolored fabric materialwith an excess of a liquid containing a dyestutf carried in a mixture ofwater, organic solvent and a thiocyanate selected from the groupconsisting of alkali-metal and ammonium thiocyanates; and removing theexcess liquid, scouring and finishing to obtain the colored double-knitmaterial.

This invention relates broadly to the art of dyeing. More particularlyit is concerned with an improved method of dyeing or coloring adouble-knit fabric material, the fibers or filaments of which comprise acellulose organic acid ester.

The filamentary cellulose esters of low hydroxyl content in thedouble-knit fabric materials that are colored by the method of thisinvention contain not more than 0.29, preferably from zero to 0.12,hydroxyl (alcoholic hydroxyl) groups per anhydroglucose unit in thecellulose molecules thereof. Best results are obtained by the use ofcellulose acetate of very high acetyl value, for instance an acetylvalue of at least 59%, advantageously above about 60%, and preferablyfrom 61 to 62.5%, calculated as combined acetic acid. Such esters of lowhydroxyl content are hereafter referred to as triesters. Cellulosetriacetate is the preferred triester. However, other lower aliphaticesters of cellulose of the aforesaid low hydroxyl content may beemployed. Examples of of such esters are cellulose formate, cellulosepropionate, cellulose butyrate, cellulose acetate-propionate andcelluose acetate-butyrate.

Aqueous dyeing of double-knit, cellulose triester-containing fabricsusually results in distortion of the doublepique stitch. It also resultsin loss of stitch definition due to mechanical agitation caused byraising of surface fibers. This stitch distortion or loss of stitchdefinition adversely affects the aesthetic characteristics of thefabric. Consequently, it is unsatisfactory to the trade.

An effort has been made to produce commercially satisfactory,double-knit, cellulose triester-containing fabrics in various colors bycoloring the yarn, e.g., by package dyeing. The colored yarn was thendouble knit, and the resulting fabric was steam-calendared(substantially nonwet finished). This technique is more expensive thanpiecedyeing the double-knit triester fabric. Furthermore, the

technique is objectionable in that package dyeing of the triester yarnseems to cause fiber brittleness.

The market for double-knit fabrics is growing rapidly. However, only arelatively small amount of synthetic yarn heretofore has been usedannually for this purpose. The above-described dyeing problem has almostcompletely precluded cellulose triester yarns from use in double-knitfabrics. The problem has been a serious one both from economic andconsumer viewpoints because of the inherent advantages, over cotton andwoolen double-knit fabrics, of cellulose triester double-knit fabricsfrom the standpoint of comfort, wrinkle-resistance, ease-of-careproperties, as well as in other useful characteristics desired by theconsumer.

The present invention is based on our discovery of a method thatprovides a solution to the above-described problem of producing acolored, double-knit, cellulose triester-containing fabric.

It is a primary object of the present invention to provide a method ofcoloring a double-knit fabric material, the fibers of which comprise acellulose organic acid ester having less than 0.29 hydroxyl groups peranhydroglucose unit, whereby after scouring and finishing there isobtained a colored double-knit fabric material comprised of theaforementioned fibers that shows no substantial loss of stitchdefinition.

Another object of the invention is to provide a method of preventingobjectionable stitch distortion in coloring double-knit fabric materialthat is comprised of fibers such as described in the preceding paragraphand, more particularly, of cellulose acetate having an acetyl value ofat least 59% calculated as combined acetic acid.

Still another object of the invention is to provide a method thatfulfills the objects described above and, additionally, yields acolored, double-knit, cellulose triestercontaining fabric whereinsubstantially no brittleness of the fiber has occurred during thecoloring or dyeing operation.

A further object of the invention is to provide a method of coloring adouble-knit, cellulose triester-containing fabric material havingcommercially satisfactory aesthetic characteristics.

Still another object of the invention is to provide a method of coloringa double-knit, cellulose triester-containing fabric material that iscommercially satisfactory from the standpoint of color fastness, hand,comfort, wrinkle-resistance, ease-of-care properties, as well as inother useful characteristics desired by the consumer.

Other objects of the invention will be apparent to those skilled in theart as the description of the invention proceeds.

In accordance with the present invention a double-knit (i.e.,circular-knit) fabric material, which is constituted of fiberscomprising an organic acid ester having less than 0,29 free hydroxylgroups per anhydroglucose unit, is contacted with an excess of a liquidcontaining a dyestufi carried (e.g., as a true solution, a colloidalsolution, a dispersion, or in any other form in which dyestuffs arepresent in dyebaths) in a mixture of water, an organic solvent, and athiocyanate selected from the group consisting of the alkali-metal(sodium, potassium, lithium, etc.) and ammonium thiocyanates. Forinstance, the dyestuif may be dissolved in a solution comprising theaforementioned ingredients. Thereafter, the excess liquid is removed,e.g., by squeezing (as by passage between adjacent moving surfaces or inany other suitable manner), or centrifugation, whereby after scouringand finishing there is obtained a colored double-knit fabric materialcomprised of the aforementioned fibers that shows no substantial loss ofstitch definition.

The process of this invention makes it possible to dye double-knitfabric materials comprised of cellulose organic acid esters of low freehydroxyl content in full shades having excellent fastness to washing,fastness to light, fastness to atmospheric fading agents such as ozoneand nitrous oxide, and excellent resistance to crocking. In fact,double-knit fabrics dyed in accordance with the present invention are soWashfast that they pass the exceptionally severe #3 A.A.T.C.C.washfastness test, even when the fabrics have not received a subsequentheat treatment.

The dyebaths that may be used in practicing the present inventioncomprise a mixture containing an organic solvent and having such solventpower that when a fabric material comprised of fibers of the usualsecondary cel lulose acetate of lower acetyl content, having an acetylvalue of 5455% calculated as combined acetic acid, is immersed in saiddyebath, said secondary cellulosse acetate fibers are coalesced and thefabric material thereof loses its fibrous character, the solvent powerof said mixture being, however, insufiicient to cause any coalescenceof, or any other substantial damage to, the aforementioned celluloseester of high acyl content,v specifically cellulose acetate fibers ofhigh acetyl content.

In a preferred form of the invention the dyebath con tains the dyestuffdissolved in a mixture, specifically a solution or a dispersion, ofwater, an organic solvent, and a thiocyanate selected from the groupconsisting of the alkali-metal and ammonium thiocyanates.

In accordance with one particularly advantageous aspect of thisinvention the dyebath contains a dyestuff dissolved, dispersed orotherwise distributed in a mixture of from, by weight, 5 to parts aceticacid, 5 to 55 parts water and 25 to 70 parts of a monohydric aliphaticalcohol represented by the general formula ROH wherein R represents analiphatic radical and, specifically, an alkyl radical, together with athiocyanate selected from the group consisting of the alkali-metal andammonium thiocyanates. In such a dyebath the proportion of the aforesaidthiocyanate in the dyebath is within the range of, by weight, from 5 to12 parts and is such that when a textile material consisting of fibersof the usual sec ondaiy cellulose acetate of an acetyl value of from 54-55%, calculated as combined acetic acid, is immersed in the said dyebaththe said secondary cellulose acetate fibers are coalesced and the fabricmaterial comprising the same loses its fibrous character.

In accordance with another specific aspect of this invention, thedyebath contains a dyestuff dissolved, dispersed or otherwisedistributed in a mixture of from 5 to parts of water and from 65 to 95parts of a monohydric aliphatic alcohol represented by the generalformula ROH wherein R represents an aliphatic radical and, specifically,an alkyl radical, together with a thiocyanate selected from the groupconsisting of the alkalirnetal and ammonium thiocyanates. The proportionof the said thiocyanate in the said dyebath is in the range of, byweight, from 8 to 14 parts and is such that when a fabric materialconsisting of fibers of the usual secondary cellulose acetate of acetylvalue of 5455%, calculated as combined acetic acid, is immersed in thesaid dyebath, the said secondary cellulose acetate fibers are coalescedand the fabric material comprising the aforesaid fibrous material losesits fibrous character.

In a further specific aspect of the instant invention, the dyebathliquor is a single-phase solvent comprising at least 30% by weight of anorganic liquid swelling agent for highly acetylatcd cellulose, at leastl0% by weight: of the solvent comprising a primary swelling agent suchas a polyhydric alcohol ether, a polyhydric alcohol ester, diacetonealcohol or an alkyl phosphate. These latter substances can be present tomake up the full minimum of 30% swelling agent or the balance can bemade up of secondary swelling agents such as carboxylic acids, e.g.,formic, acetic or propionic acids, glycols, e.g., ethylene glycol,alcohols of the general formula represented by ROH, wherein R representsa hydrocarbon radical and, specifically such alcohols as, for example,the various alkanols, for instance, methyl, propyl, butyl and isobutylalcohols and, particularly, ethyl alcohol, and the like. To thesingle-phase solvent there is added an alkali-metal or amoniumthiocyanate in an amount ranging from about 4 to 12% by weight of thesolvent, preferably from about 5 to about 11% by weight thereof.

To complete the dyebath there is dissolved in the solvent a dyestulf forthe cellulose ester. The dyestuff is generally employed in an amount upto about 5% by weight of the solvent, and preferably in an amountranging from about 0.2% to about 3% by weight thereof. Representativeprimary swelling agents that can be used include beta-phenoxyethanol,beta-n-butoxyethanol, beta-methoxyethanol, n-butoxyethoxyethanol,ethylene glycol monoacetate, glycerine diacetate, glycerine triacetate,diacetone alcohol, triethyl phosphate, tripropyl phosphate, and thelike. In some instances, such as when using beta-phenoxyethanol, theprimary swelling agent will not be sufficiently soluble in the water sothat, in order to establish a single-solvent phase, there can be addedanother primary swelling agent such as diacetone alcohol or a secondaryswelling agent such as acetic acid which is miscible with both the waterand beta-phenoxyethanol. The use of a solvent comprising at least 20% byweight of acetic acid prevents phase separation and yields especiallygood dyeings, even with relatively water-insoluble swelling agents.

A wide variety of dyestuffs may be employed in practicing the presentinvention, including acid dyestuffs, premetallized dyestuffs, directcotton dyestuifs and leuco vat ester dyestulfs, none of which has anyappreciable afiinity for cellulose triesters, specifically cellulosetriacetate, when applied from dispersions in water containing dispersingagents. Disperse cellulose acetate dyestuffs, especially those of theknown slow-dyeing, high-temperature type, may also be used. Examples ofsuitable materials include' those sold under the following names.Premetallized dyestuffs:

Irgalan Yellow 2 RL (C.I. Acid Orange 85) Irgalan Rubine RL (C.I. AcidViolet Irgalan Bordeaux 2 BL (C.I. Acid Red 218) Irgalan Brown 2 RL(C.I. Acid Brown 45) Irgalan Brown 7RL (C.I. Acid Brown 47) IrgalanOrange RL (C.I. Acid Orange 86) Irgalan Red 36 (C.I. Acid Red 220)Irgalan Brown 5R (C.I. Acid Brown 48) Irgalan Brown 2GL (C.I. Acid Brown44) Irgalan Brown BBL (C.I. Acid Brown 46) Irgalan Yellow GL (C.I. AcidYellow 114, Color Index, second edition, vol. I, p. 1050) Irgalan Green3GL (C.I. Acid Green 57) Irgalan Olive BGL (C.I. Acid Black 64) GycsolanBlack WAL (C.I. Acid Black 52, Cl. Part II Cibalan Corinth BL (C.I. AcidViolet 87) Cibalan Green GL (C.I. Acid Green 43) Vitrolan Orange R (C.I.Acid Orange 76, Cl. Part Direct cotton dyestuffs:

Amanil Chrysophenine G (C.I. Direct Yellow 12,

Cl. Part II 24895 Acid dyestuffs:

Xylene Milling Yellow P (C.I. Acid Yellow 61) Orasol Navy Blue RB (C.I.Solvent Blue 1) Orasol Violet 3B (C.I. Solvent Violet 6) C I.--CelorIndex, second edition, 1056 and supplements.

Erio Anthracene Rubine 3GP (C.I. Acid Red 57) Artol Blue GL (No. 833,first edition of Color Index) Leuco vat ester dyestuffs:

Indigosol Orange HR (C.I. Solubilized Vat Orange 5,

Cl. Part II 73336) Indigosol Brown IRRD (C.I. Vat Brown 5, Cl. Part II73411) Indigosol Bordeaux 12RN (C.I. Vat Red 4) Indigosol Green lGG(C.I. Solubilized Vat Green 2, 0.1. Part II 59831) Indigosol Yellow R(C.I. Solubilized Vat Yellow 6) Indigosol Red 12B (C.I. Solubilized VatRed 8) Indigosol Olive Green 1B (C.I. Solubilized Vat Green 3, 0.1. PartII 69501) Indigosol Brilliant Pink B (C.I. Solubilized Vat Red 9)Indigosal 04B (Cl. Solubilized Vat Blue 5, Cl. Part II, 73066) IndigosolScarlet 1B (C.I. Solubilized Vat Red 6,

Cl. Part II 73356) Indigosol Golden Orange 12R (C.I. Solubilized VatOrange 2, C.I. Part II 59706) Algosol Blue 06B (C.I. Solubilized VatBlue 9, 0.1.

Part II 73071) Disperse cellulose acetate dyestuffs:

Amacel Yellow CW (C.I. Disperse Yellow 42, OJ.

No. 10338) Unclassified dyestuffs:

Alcian Blue 6 GN (C.I. Ingrain Blue I, C.I. Part II *C.I.-Color Index,second edition, 1956 and supplements.

The dye-containing liquid composition or dyebath is preferably appliedto the double-knit fabric material by a padding operation in which thesaid fabric material passes through the dyebath in a pad box, and isthen squeezed between pad rolls to eliminate the excess liquid. Thetemperature at which the dyebath is applied may range, for example, fromto 30 C., a temperature of about C. to about C. being especiallysuitable. With the higher temperatures the water content of the dyebathis preferably rather high while the thiocyanate content is lower toavoid the possibility of damage due to coalescence of the celluloseester fibers of which the double-knit fabric is comprised.

The double-knit fabric material that is colored in accordance with thepresent invention is produced by circular knitting a fibrous materialthat comprises a cellulose triester of the kind hereinbefore described.Preferably the double-knit fabric is slit to form an open-width fabricbefore it is brought into contact with the dyebath.

After the fabric has been contacted with an excess of the dyebath (as byimmersion therein), it may be rinsed in cold water to terminate thedyeing action and to remove any loosely adhering dyestulf The dyestulfis fixed on the fabric by suitable treatment, e.g., by a salt rinse ofthe kind, and used in the manner, described in Ward and Warner U.S.Patent 3,119,648, dated Jan. 28, 1964, more particularly in column 4,line 12, through line 9 in column 5 thereof. Following other appropriaterinse or rinses, the colored fabric is scoured and finished, includingdrying.

Various other means may be employed for fixing the dyestuif on thefabric. For example, such fixing agents may be comprised of salts suchas those used in the salt rinse baths described in the aforementionedU.S. Patent No. 3,119,648, and which are preferably salts of monovalentcations, such as the alkali-metal and ammonium ions, and the anions ofmineral acids or lower alkanoic acids. Typical examples of such saltsare sodium acetate and ammonium acetate.

When the dyestufi is a leuco vat ester, a cold water rinse preferablyprecedes the aforesaid hot salt solution treatment if the latter is tobe used. A suitable developing ing an organic solvent, more particularlya mixture of water and an organic solvent, the cellulose triester fibersgo through a solvated or plasticized state. This physical condition ofthe fibers can then be advantageously utilized under pad pressure todistinctly change the aesthetic characteristics of the double-knitfabric, e.g., fabric thickness and fabric firmness, and to effect thisresult without changing the surface or stitch appearance of the fabric.

Firming and thickening effects of the double-knit fabric can becontrolled by introducing another (i.e., different) kind or kinds offibrous or filamentary material into the yarn to be double knit. Suchdifferent fibrous material generally constitutes a minor amount (lessthan 50%) by weight of the yarn to be knitted (and of the doubleknitfabric) while the cellulose triester, specifically cellulose triacetate,fibrous material constitutes the remainder. Thus the amount of thedifferent fibrous material may range, for example, from about 5% toabout 45% by weight of the double-knit fabric. The different fibrousmaterial may, of course, constitute a major amount (more than 50%, e.g.from 51% to about 70 or or more) by weight of the yarn to be knittedwhile the cellulose triester fibrous material constitutes the remainder;however, when this is done one loses many of the advantages inherent inthe use of cellulose triester fibers in making the double-knit fabric.

The double-knit fabric material, when wet with dyebath, can be rinsedwith cold water prior to a hot salt solution treatment such as thatdescribed in the aforementioned U.S. Patent No. 3,119,648. This isparticularly desirable when the double-knit fabric contains animal orpolyamide fibers such as wool, fibers from zein, silk, nylon or thelike, in addition to cellulose triester fibers, and it is desired tocolor the triester fibers selectively. On the other hand, if uniondyeings are desired, i.e., if it is desired to color both the cellulosetriester fibers and the polyamide, there should not be a cold-waterrinse; instead, the double-knit fabric should be passed directly fromthe dyebath to a hot salt solution if the latter is to be used. Whensuch a union dyeing is desired, best results are achieved when thedyestutf is an acid dye, when the salt is sodium chloride, and when thetime of contact between the double-knit fabric and the hot salt solutionis at least about 5 minutes. Up to about 1 gram per liter of a loweraliphatic acid such as acetic acid can be included in the hot saltsolution to aid in dyeing the polyamide.

In addition to the aforementioned polyamide fibers, other fibers thatmay be used to modify the cellulose triester. fibers to produce a yarnof blended fibers that is circular knit to make a double-knit fabricinclude polyester fibers such as those comprised of polyethyleneterephthalate, polypropylene fibers, polyvinylidene cyanide fibers,acrylic (polyacrylic) fibers such as those made of acrylonitrilepolymers (homopolymeric and copolymeric acrylonitriles), viscose andcuprammonium rayons, cotton, linen, ramie, sisal and the like. Of courseone should not use any modifying fibers that are deleteriously affectedby the dyebath.

In order that those skilled in the art may better understand how thepresent invention can be carried into effect, the following examples aregiven by way of illustration and not by way of limitation. All parts andpercentages are by weight unless otherwise stated.

EXAMPLE I A circular knit fabric of yarn composed of 100% of cellulosetriacetate having an acetyl value of 61.3% by weight calculated ascombined acetic acid was immersed in a 2-roll pad dyeing machine in adyebath containing 2% of Irgalan Yellow GL (C.I. Acid Yellow 114) dyedissolved in a liquid composed of 20 grams/liter of acetone-freediacetone alcohol, 250 grams/liter of glacial acetic acid, 100grams/liter of sodium thiocyanate and 450 grams/liter of water. Themachine operated at a speed of yards/minute under a pressure of 6 tons,and the temperature of the dyebath was 28 C.

After the fabric was padded through the dyebath in one immersion, it wasrinsed for minutes on winch in cold water and again for 20 minutes onthe winch with warm water. This was followed by a scouring on the winchfor /2 hour using a solution of /2 gram/liter of Igepon fatty alkylester sulfonate anionic surfactant at 55-60 C., warm rinsing extractingand drying. A satisfactory dyed fabric having substantially no loss ofstitch definition was obtained.

EXAMPLE II The procedure of Example I was repeated except that thedyestuff is Vitrolan Orange R (Cl. Acid Orange 76, Cl. Part II No.18870). Equivalent results are obtained.

EXAMPLE III The procedure of Example I is repeated except that thecircular knit fabric is produced with yarn composed of 50% of cellulosetriacetate and 50% of cotton, and the liquid in which the dye isdissolved is composed of 20% of triethyl phosphate, of glacial aceticacid, 10% of sodium thiocyanate, and 45% of water, the percentages beingbased on the weight of the total liquid. A dyed fabric having littleloss of stitch definition and particularly good colorfastness and levelof dyeing is obtained.

satisfactorily dyed circular knit fabrics having little loss of stitchdefinition could be obtained following the procedure of the exampleswith any of the dyes listed above.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations may be madetherein without departing from the spirit of our invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A colored double-knit fabric material free of distortion in thecourses and wales of the double-pique stitch and having substantialretention of stitch definition, the fibers of which are substantiallyfree of brittleness and comprise a cellulose organic acid ester havingless than 0.29 free hydroxyl groups per anhydroglucose unit, produced bya method which comprises: contacting the uncolored double-knit fabricmaterial with an excess of a liquid containing a dyestuff carried in amixture of water, an organic solvent, and a thiocyanate selected fromthe group consisting of the alkali-metal and ammonium thiocyanates; andremoving the excess liquid from the thusly treated fabric material,scouring and finishing to obtain the colored double-knit material.

2. The product of claim 1 wherein the cellulose organic acid ester iscellulose acetate having an acetyl value of at least about 59 percentcalculated as combined acetic acid.

3. The product of claim 1 wherein the fibers of which the double-knitfabric material is constituted additionally includes fibers of adifferent composition selected from the group consisting of cellulosefibers, animal fibers, polyamide fibers, polyester fibers andpolyacrylic fibers.

4. A colored circular knit fibrous material free of distortion in thecourses and wales of the double-pique stitch and having substantialretention of stitch definition, the fibers of which are substantiallyfree of brittleness and comprise a cellulose organic acid ester havingless than 0.29 free hydroxyl groups per anhydroglucose unit, produced bycontacting said fabric material with an excess of a liquid containing adyestuff carried in a mixture of water, an organic solvent, and athiocyanate selected from the group consisting of the alkali-metal andammonium thiocyanates; and removing the excess liquid from the thuslytreated fabric material, scouring and finishing to obtain a coloreddouble-knit fabric material.

5. A colored circular knit fibrous material free of distortion in thecourses and wales of the double-pique stitch and having substantialretention of stitch definition, the fibers of which are substantiallyfree of brittleness and comprise a cellulose organic acid ester havingless than 0.29 free hydroxyl groups per anhydroglucose unit, produced byslitting the resulting fabric to form an open-width fabric; contactingthe said open-width fabric with an excess of a liquid containing adyestuif carried in a mixture of water, an organic solvent, and athiocyanate selected from the group consisting of the alkali-metal andammonium thiocyanates; and removing the excess liquid from the thuslytreated fabric material, scouring and finishing to obtain a coloreddouble-knit fabric material in open width.

6. A double-knit fabric material free of objectionable stitch distortionfrom coloring, the fibers of which are substantially free of brittlenessand comprise cellulose acetate having an acetyl value of at least about59 percent calculated as combined acetic acid, produced by pad dyeingthe said fabric material using a dyebath containing a dyestutf dissolvedin a solution comprising water, a monohydric alcohol, and a thiocyanateselected from the group consisting of the alkali-metal and ammonium thiocyanates; and scouring and finishing the pad-dyed fabric material.

7. A colored double-knit fabric material free of distortion in thecourses and Wales of the double-pique stitch and having substantialretention of stitch definition, the filaments of which are substantiallyfree of brittleness and comprise cellulose acetate having an acetylvalue of at least about 59 percent, calculated as combined acetic acid,produced by immersing said fabric material in a dyebath containing adyestuif dissolved in a solution comprising water, a monohydricaliphatic alcohol, and a thiocyanate selected from the group consistingof the alkali-metal and ammonium thiocyanates; and squeezing the thuslytreated fabric material by passage between adjacent moving surfaces toremove excess dyebath solution, scouring and finishing to obtain acolored doubleknit fabric material comprised of the aforementionedfilaments that shows no objectionable stitch distortion.

8. The product of claim 7 wherein the fabric material is c'olored with adisperse cellulose acetate dyestutf.

9. The product of claim 7 wherein the fabric material is colored in adyebath containing a monohydric aliphatic alcohol which is a loweralkanol.

10. The product of claim 7 wherein the fabric material is colored in adyebath containing a dyestufi dissolved a solution comprising, byweight, from 5 to 25 parts of acetic acid, from 5 to 55 parts of water,from 25 to parts of an alcohol, and from 5 to 12 parts of a thiocyanateselected from the group consisting of the alkali-metal and ammoniumthiocyanates.

11. The product of claim 7 wherein the fabric material is colored in adyebath containing a dyestuif dissolved in a solution comprising, byweight, from 5 to 35 parts of water, from 65 to parts of an alcohol, andfrom 8 to 14 parts of a thiocyanate selected from the group consistingof the alkali-metal and ammonium thiocyanates.

12. The product of claim 7 wherein the fabric material is colored in adyebath, which in addition to the dyestulf, comprises a single-phasesolvent consisting of at least 20 percent by weight of water and atleast 30 percent by weight of an organic swelling agent for the definedcellulose ester, at least 10 percent by weight of said solvent being aprimary swelling agent selected from the group consisting of polyhydricalcohol ethers, polyhydric alcohol esters, diacetone alcohol and alkylphosphates, said solvent having dissolved therein from 4 to 12 percentby weight of a thiocyanate selected from the group consisting of thealkali-metal and ammonium thiocyanates.

13. The product of claim 7 wherein the fabric material is colored withan acid dyestutf.

References Cited UNITED STATES PATENTS J. TRAVIS BROWN,

Primary Examiner.

T. J. HERBERT, 111., Assistant Examiner.

US. Cl. X.R.

